1. Field
The invention relates to a device for the centralized management of measurements and data relating to the liquid and gas flows needed for the correct operation of a combustion engine and/or a vehicle.
2. Introduction
Combustion engines use a plurality of flows more particularly fuel, engine lubrication oil, engine cooling fluid, brake fluid for the vehicles, the liquids participating in the post-treatment of the polluting emissions (urea solution for neutralizing nitrogen oxides for example serine for the regeneration of the additive particulate filter).
The combustion of the air/fuel mixture in a combustion engine entails emissions of greenhouse effect gas (carbon dioxide) and pollutants (unburnt hydrocarbons, carbon monoxide, nitrogen oxides, particles, aldehydes).
The always stricter regulations relating to the emissions of greenhouse effect gas as well as to the polluting emissions entail always more important efforts for engine manufacturers. The taking into consideration, by the engine computer, of the quality of the various liquid and/or gas flows, such as fuel, inlet air, exhaust gas and the fluids needed for the various post-treatment steps in particular tends to generalise, so as to optimise combustion engines with the aim of minimizing the consumption of fuel and thus the greenhouse effect exhaust gas as well as the polluting emissions during the whole life of the combustion engine and/or the vehicle provided with a combustion engine.
It is known that the quality of fuels has a direct influence on performances, consumption, polluting emissions and greenhouse effect exhaust gas.
A. DOUAUD has proved, as from 1983, for controlled ignition engines, the connection between the quality of gasoline, the adjustments of the engine and the occurrence of the knocking phenomenon. J. C. GUIBET, as from 1987, in the reference book Carburants et Moteurs proved the interactions between the quality of the fuel and the engine and the influence thereof in the engine combustion setting and adjustment models. More recently, in 1997, in a publication, A. GERINI analyzes the sensitivity to the gasoil parameters of a direct injection diesel engine on a vehicle. Eventually, in 2003, N. HOCHART provided a modelling of pollutant emissions of present engines using gasoline, diesel for light vehicles or trucks, by varying the quality of fuel by modifying the refining bases used in the mixtures.
The composition and the quality of fuels, although it is defined by standards and more particularly standards EN 590 and EN 228 in Europe, vary over time. Quality changes as a function of deliveries, distributors, seasons and prevailing regulations. It is thus estimated that the physico-chemical properties of fuels can vary from 15 to 40% or more around the average values defined in the standards. As antipollution standards are always stricter, there a need to determine the quality of fuel and to take the same in consideration while adjusting the engine parameters such as injection, combustion and post-treatment parameters. The qualitative measurement of fuel and the use thereof by the engine computer are more particularly examined in documents WO9408226, U.S. 2004000275, FR-2542092, U.S. Pat. No. 5,126,570, U.S. Pat. No. 5,262,645, U.S. Pat. No. 5,239,860 and WO2006100377.
With the same goal of limiting polluting emissions, methods describing engine control parameters adjustments as a function of the onboard analysis of exhaust gas, document WO02095376 can be cited, which describes a modular structure method enabling the detection and characterisation of liquid and solid particles and gas constituents of exhaust gas which can be used to adjust the engine and the structural elements for exhaust gas.
Some post-treatment methods include the utilization of reagent fluids or catalysts. The system of conversion of nitrogen oxides by a reaction with a urea solution and the method converting particles using a liquid additive can be more particularly cited. Such methods require the addition of additional storage tanks, the volume and mass of which increase the constraints of bulk and the mass of the combustion engine and/or of the vehicle. Managing at best the utilization of such fluids thus become a strategy so as to minimize the bulk and added mass. To ensure the efficiency of such post-treatment methods, the quality of catalysts and reagents implied in such methods is of utmost importance; it is legitimate to consider measuring the quality thereof using an onboard system.
In spite of the regulatory or internal provisions recommended by fuel distributors and vehicle manufacturers, such as refiners and distributors' quality improvement procedures, the display of the nature of fuels at the filling stations, the diameter of the dispensing nozzle and the diameter of the tank filling system in particular, many users willingly or not introduce a non-adapted fuel into the tanks of their vehicles. An increasing number of vehicles is used with products which are not certified by the manufacturers and the customs services like used frying oils, non-esterified vegetable oils, domestic fuel oils, causing important damages to the power unit, the fuel supply system and the post-treatment system. The damages (fouling of injectors, of the engine, of the tank, choking of the filters, seizing of the pumps, deactivation of catalysts) can be severe, severely impact the engine injection and combustion phases and increase the regulated or not polluting emissions, which can lead to the engine break. Similarly, some fuels such as water/gasoil or gasoline/alcohol or gasoil/bio-fuels emulsions can be instable and the quality thereof can deteriorate over time (storage stability, phenomenon of de-mixing between gasoline and ethanol or gasoil and diester above 5%). Such various sources of deterioration of the nature of the fuel potentially entail an increase in the vehicle pollution, damages to the vehicle or at least important corrective operations. Thus, concepts and methods aim at providing preventive safety to the elements of the power unit of a vehicle equipped with a combustion engine, prior to or during the ignition phase further to deterioration of the nature of the fuel contained in the tank and the fuel supply system. Such concepts and systems involve the measurement of the fuel quality, ideally in the fuel supply system.
For example, the method described in document FR0607420 aiming at providing safety to the elements of the power unit further to the detection of the fuel deterioration can be mentioned.
Post-treatment methods such as a diesel particulate filter in particular contain catalysts which are particularly sensitive to sulphur compounds.
Such sulphur compounds, as a matter of fact, make catalysts less active and also affect the efficiency of the methods for converting post-treatment polluting emissions. The law very significantly reduced the maximum sulphur content of fuels; more particularly diesel today in Europe has a sulphur content of less than 50 ppm and the future legislation will reduce this sulphur content to less than 10 ppm.
Such specifications on the sulphur content in fuels make it possible for the post-treatment methods sensitive to sulphur compounds to extend their lives and the duration of correct operation thereof. This also makes it possible for such post-treatment methods to progress by making it possible to use more and more developed catalysts that have an increased sensitivity to sulphur compounds. Engine lubrication oils, due to their design, contain high sulphur compound contents. During the operation of the engine, a part of such sulphur compounds existing in the engine lubrication oil can participate in the combustion and thus circulate along the post-treatment line. Such sulphur compounds initially existing in the lubrication oil thus participate, as those from the fuel, in the deactivation of post-treatment catalysts. Thus, in order to provide an efficient and extended post-treatment, it is important to follow the quality of oil and the evolution thereof over time. Thus, the quality of the lubrication oil must be taken into account by the engine computer and the optimisation of post-treatment.
The method described in details in document KR20020049612 disclosing a system for measuring the quality of the engine oil using spectroscopic methods can be mentioned.
The extension of guarantees provided by the engine manufacturers leads the latter to make the combustion engines more robust, and thus to inform, as soon as possible and as best as they can, the user or the companies in charge of servicing the vehicles, of the need for possible maintenance operations on the combustion engine or the vehicle.
As a matter of fact, to provide such guarantees, it is legitimate for the manufacturers to make sure that the utilization of the combustion engine and/or of the vehicle is complying and that the servicing operations inherent in the correct operation of the combustion engine and/or of the vehicle such as lubrication oil changes, brake fluid changes or cooling fluid changes are carried out at the frequency recommended by the manufacturers.
In addition, to provide a long term support of the engine user, the manufacturer more and more often supplies the latter with real time information on the condition of the engine and the next maintenance operations. The mile countdown displayed on the dashboard of some vehicles to inform the user of the number of kilometers to be covered prior to the next lubrication oil change operation, can be cited. It can be considered to supply the user or the engine maintenance companies with other real time information relating to the quality of the brake fluid for a vehicle and the engine cooling fluid, for example. Therefore, it becomes important to measure the quality of such fluids and to follow the evolution thereof over time. Conventional methods consist in measuring the glycol content existing in the cooling fluid and the refraction index makes it possible to characterize the quality of the brake fluid in a vehicle.
The measurement and tracking of the quality of each one of such fluids needed for the correct operation of a combustion engine and more particularly fuel, exhaust gas, lubrication oil, cooling fluid and brake fluid for a vehicle can be carried out using various analyzing techniques. Spectroscopic and in particular infrared, near infrared, ultraviolet and visible spectroscopic methods, electric conductivity and refraction index can more particularly be mentioned.
Each one of such systems for measuring the quality of the various fluids enabling a better management of the engine parameters, for example aboard a vehicle, must meet precise criteria such as resistance to vibrations or resistance to important temperature variations. Such systems must be conditioned so as to be able to operate under severe environments (dust, soot, smoke).
In addition, it shall be necessary to develop as many physical and connector technology interfaces with the engine computer as qualitative analyses of each flow, analyzed separately.
In addition, it is advisable to consider measuring the quality of some flows at various places; as a matter of fact, the measurement of qualitative exhaust gas can be carried out upstream or downstream of the post-treatment methods with a particular view to ensuring the correct operation of said methods.
Similarly, it is advisable to carry out the measurement of the fuel quality in the fuel supply pipe and in the fuel line supplying the engine: the first location will make it possible to ensure the compliance of the fuel introduced into the tank with the optional aim of warning the user or to protect the power unit; the second location of the measurement of quality will mainly enable the optimization of the engine control parameters.
Finally and more particularly for the systems aboard vehicles, the bulk and mass are important constraints; as a matter of fact, the space available in a tourist vehicle is particularly limited and any increase in the mass of a vehicle more particularly induces increases in the consumption of fuel.